Regi Davis

While undergoing aggressive cancer treatment, Izzie focuses on planning Meredith and Derek's wedding; Callie's father visits; Owen seeks help with his PTSD.

All reassess their personal lives after witnessing a chance reunion between two long-lost lovers in the emergency room; Karev treats a troubled teen (Demi Lovato); Meredith shares her suspicions with Cristina.

The team pursues a serial killer in Milwaukee, with three fewer members since Hotch asked to be transferred, Prentiss quit, and Gideon is missing.

Michael's medical condition forces him to go to the hospital; Lincoln and Sucre get into an explosive situation; Agent Self meets with a shocking ally.

When Gibbs and McGee travel to Russia to escort a computer engineer home, the mission is compromised, and they must hide from a Russian mercenary group that is hunting them.

After a series of brutal and deadly attacks, Nick & Hank find an unlikely lead in a local nursing home; Eve goes to Adalind to get answers.